Weissella Ceti Research Articles

Bioprotective potential of Latilactobacillus sakei and Latilactobacillus curvatus in smoked chicken legs with modified atmosphere packaging

The effects of inoculation with bioprotective bacteria (Latilactobacillus sakei and Latilactobacillus carvatus) on the bacterial succession, physicochemical properties, volatile organic compound (VOCs), and sensory attributes of smoked chicken legs stored in modified atmosphere packaging (MAP, 60% CO2 and 40% N2) at 4 °C for 28 days were investigated. Compared with the control (without inoculation), inoculation with L. sakei and L. curvatus inhibited the growth of common spoilage bacteria (Serratia proteamaculans, Weissella ceti, and Pseudomonas fragi) in smoked chicken legs stored in MAP. They significantly (P < 0.05) decreased the levels of lipid oxidation and spoilage markers such as ethanol, 1-octen-3-ol, carbon disulfide, cyclooctanol, 2,3-butanediol, and 3-methyl-1-butanol, slowed down the deterioration of the surface skin color and odor, and prolonged the shelf-life of the product. Inoculation with L. sakei and L. curvatus extended the shelf life of smoked chicken legs stored in MAP by 7 and 14 days, respectively.

Comparative polyphasic characterization of Weissella strains isolated from beaked whale and rainbow trout (Oncorhynchus mykiss): confirmation of Weissella ceti sp. nov. and description of the novel Weissella tructae sp. nov. isolated from farmed rainbow trout.

The weissellosis agent bacterium (WS08T = CBMAI 2730) was isolated from diseased rainbow trout (Oncorhynchus mykiss) in Brazil. The whole genome sequence of this strain was compared with the Mexican W-1 strain, also isolated from diseased rainbow trout, and with the Weissella ceti type strain CECT 7719T (= 1119-1A-09T = CCUG 59653T), recovered from the beaked whale. Digital DNA-DNA hybridization pairwise analyses scored 98.7% between the Mexican W-1 and Brazilian WS08T but just 24.4% for both fish isolates compared to the W. ceti type strain CECT 7719T. The 16S rRNA gene sequence comparisons with isolates of W. ceti, available at GenBank, were conducted. All rainbow trout-pathogenic isolates grouped close (97% bootstrap confirmation), but when this group was compared to the W. ceti type strain CECT 7719T the similarity varied from 78.9 to 79.1%. Phenotypic assays were also conducted, and the W. ceti type strain diverged from WS08T and W-1 in the hydrolysis of aesculin, D-mannose, and potassium gluconate and in the hydrolysis of hippurate. Moreover, WS08T and W-1 showed weak growth at 5°C whereas no growth was observed for W. ceti CECT 7719T. The major fatty acids (> 10% total fatty acids) presented by WS08T and W-1 were summed feature 8 (C18:1 ω7c/C18:1 ω6c), summed feature 3 (C16:1 ω6c/C16:1ω7c), and C16:0. The results of phylogenetic and phenotypic analyses clearly differentiated the W. ceti CECT 7719T type strain from the assessed pathogenic strains obtained from rainbow trout. Therefore, Weissella strains isolated from rainbow trout, here represented by strain WS08T (= CBMAI 2730), should be known as members of a novel species for which the name Weissella tructae sp. nov. is proposed.

Weissellosis in rainbow trout in Colombia

Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.

First description of Weissella ceti associated with mortalities in farmed rainbow trout (Oncorhynchus mykiss) in Peru

Mortalities of up to 60% farmed rainbow trout (Oncorhynchus mykiss) were recorded in six floating cages farms in the Lake Titicaca during the wet season (December to April) of 2018. Fish presented uni or bilateral exophthalmia, ocular hemorrhages and melanosis. Necropsy showed severe hemorrhage in swim bladder, brain, liver and muscle, splenomegaly, and gut congestion. Histology revealed retrobulbar hemorrhage with macrophage infiltration, multifocal necrosis in several tissues, meningitis, splenitis, epicarditis, and congestion. After microbiological culture in blood agar, flat and circular colonies with smooth edges and a zone of α-hemolysis were observed. The presence of Weissella ceti was confirmed through biochemical and molecular analysis (16S rRNA gene sequence analysis), without differences between Peruvian isolates. Worldwide, W. ceti isolates from rainbow trout were similar using 16S rRNA gene sequence, however, showed discrepancies between those isolates from different hosts. Finally, Koch's postulate was confirmed with experimental infections using rainbow trouts (~9 cm) infected intraperitoneally (0.1 mL of 104 CFU). After 21 days, clinical signs and lesions similar to the recorded in natural outbreaks were observed, cumulative mortality rate was 90% and bacteria was successfully recovered from both moribund and survivor fish. This is the first report and description of weissellosis caused by Weissella ceti isolated from rainbow trout cultured in Lake Titicaca, Peru and it is the first report of the primary isolation of this bacterium on TSA and TYES media instead of TSAB medium.

Isolation characterization, virulence potential of Weissella ceti responsible for weissellosis outbreak in rainbow trout (Oncorhynchus mykiss) cultured in Mexico.

Weissella ceti, a Gram-positive nonmotile bacterium, is currently an emerging pathogen within rainbow trout (Oncorhynchus mykiss) farms in China, Brazil, the United States, and Japan. This study is the first to isolate, identify, and characterize W.ceti isolates from rainbow trout farmed in Mexico. In late 2015, a severe disease outbreak caused a 60% mortality rate among 20,000 fish. The diseased rainbow trout (100-300g average) exhibited severe cachexia, body darkening, abdominal distension, exophthalmia, haemorrhages, and corneal opacity. Internally, diseased fish had pale gills; multifocal, disseminated whitish spots on the liver; haemorrhages in the swim bladder, ovary, and on the parietal surface of the muscle; and hearts with pseudo-membrane formation. Histologically, lesions were characterized by corneal oedema, degenerative and necrotic hepatitis, and meningitis. A brain (W-1) and kidney (W-2) isolate were identified as W.ceti through polyphasic taxonomy, which included phenotypic characterization and 16S rRNA sequencing. RAPD and ERIC-PCR analyses demonstrated genetic homogeneity among the Mexican isolates. Virulence tests in rainbow trout through intraperitoneal W.ceti injections at concentrations of 1×104 , 1×105 , and 1×106 CFU per fish resulted in cumulative mortality rates of 25%, 62.5%, and 87.5%, respectively, as well as the same clinical signs of hemorrhagic septicaemia as were recorded for the natural outbreak. The present report is the first to confirm the presence of W.ceti in Mexico, thus extending the known geographical distribution of this pathogen across the Americas.

First isolation of Weissella ceti responsible for outbreaks of weissellosis in farmed rainbow trout in Japan.

First isolation of Weissella ceti responsible for outbreaks of weissellosis in farmed rainbow trout in Japan.

A lytic bacteriophage of the newly emerging rainbow trout pathogen Weissella ceti

This study was conducted to isolate and characterize a bacteriophage of a newly emerging pathogen, Weissella ceti, which causes weissellosis outbreaks of intensively farmed rainbow trout worldwide. The phage appeared together with the cultured Weissella ceti during isolation of pathogen from kidney of diseased rainbow trout. The morphological, physiological, proteomic and lytic spectrum were characterized. This phage, named PWc, belonged to the family Siphoviridae and possessed an isometric head (approximately 65 nm in diameter) and a flexible, non-contractile tail of 170–180 nm in length. The latent time and burst size of PWc were approximately 25 min and 16 PFU/infected cells, respectively. The PWc was relatively stable over a wide range of temperatures and pH values and possessed a broad lytic spectrum, lysing all 36 tested W. ceti strains isolated from diseased rainbow trout in Japan. The protein profile of the phage was obtained using SDS-PAGE analysis, and the potential packaging strategy was determined based on terminase large subunit sequence analysis. This is the first study to investigate a lytic bacteriophage of a newly emerging pathogen W. ceti that causes infectious disease in rainbow trout.

Assessing the impact of swimming exercise and the relative susceptibility of rainbow trout Oncorhynchus mykiss (Walbaum) and Atlantic salmon Salmo salar L. following injection challenge with Weissella ceti.

Assessing the impact of swimming exercise and the relative susceptibility of rainbow trout Oncorhynchus mykiss (Walbaum) and Atlantic salmon Salmo salar L. following injection challenge with Weissella ceti.

Comparative genome analysis of Weissella ceti, an emerging pathogen of farm-raised rainbow trout.

BackgroundThe genus Weissella belongs to the lactic acid bacteria and includes 18 currently identified species, predominantly isolated from fermented food but rarely from cases of bacteremia in animals. Recently, a new species, designated Weissella ceti, has been correlated with hemorrhagic illness in farm-raised rainbow trout in China, Brazil, and the USA, with high transmission and mortality rates during outbreaks. Although W. ceti is an important emerging veterinary pathogen, little is known about its genomic features or virulence mechanisms. To better understand these and to characterize the species, we have previously sequenced the genomes of W. ceti strains WS08, WS74, and WS105, isolated from different rainbow trout farms in Brazil and displaying different pulsed-field gel electrophoresis patterns. Here, we present a comparative analysis of the three previously sequenced genomes of W. ceti strains from Brazil along with W. ceti NC36 from the USA and those of other Weissella species.ResultsPhylogenomic and orthology-based analyses both showed a high-similarity in the genetic structure of these W. ceti strains. This structure is corroborated by the highly syntenic order of their genes and the neutral evolution inferred from Tajima’s D. A whole-genome multilocus sequence typing analysis distinguished strains WS08 and NC36 from strains WS74 and WS105. We predicted 10 putative genomic islands (GEI), among which PAIs 3a and 3b are phage sequences that occur only in WS105 and WS74, respectively, whereas PAI 1 is species specific.ConclusionsWe identified several genes putatively involved in the basic processes of bacterial physiology and pathogenesis, including survival in aquatic environment, adherence in the host, spread inside the host, resistance to immune-system-mediated stresses, and antibiotic resistance. These data provide new insights in the molecular epidemiology and host adaptation for this emerging pathogen in aquaculture.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2324-4) contains supplementary material, which is available to authorized users.

Genomics of Weissella cibaria with an examination of its metabolic traits.

Weissella is a genus of lactic acid bacteria (LAB) consisting of species formerly included in the Leuconostoc paramesenteroides group. Similar to other LAB, they are commonly found in fermented foods but have also been isolated from environmental and human samples. Currently there are 20 recognized species. Herein, three Weissella cibaria genomes were sequenced using Illumia Mi-Seq and Roche 454 technologies. Annotation was performed using the Prokka and JGI IMG pipelines. A thorough analysis of the genomics of the W. cibaria strains was performed, in addition to brief comparative analyses of the genus Weissella as a whole. Genomic sequence data from the newly sequenced W. cibaria strains and data available in GenBank for other Weissella strains was used (n = 10; four Weissella cibaria, one Weissella ceti, one Weissella confusa, one Weissella halotolerans, two Weissella koreensis and one Weissella paramesenteroides). The genomes had sizes varying from 1.3 to 2.4 Mb. DNA G+C contents ranged from 35 to 45 mol%. The core- and pan-proteome at genus and species levels were determined. The genus pan-proteome was found to comprise 4712 proteins. Analysis of the four W. cibaria genomes indicated that the core-proteome, consisting of 729 proteins, constitutes 69 % of the species pan-proteome. This large core-set may explain the divergent niches in which this species has been found. In W. cibaria, in addition to a number of phosphotransferase systems conferring the ability to assimilate plant-associated polysaccharides, an extensive proteolytic system was identified.

Characterization of Weissella ceti infections in Brazilian rainbow trout, Oncorhynchus mykiss (Walbaum), farms and development of an oil‐adjuvanted vaccine

Weissella ceti is an emerging bacterial pathogen that affects rainbow trout, Oncorhynchus mykiss (Walbaum), farms. The aims of this study were to genotype W.ceti strains isolated from distinct geographical origins and to determine the efficacy of an oil-adjuvanted vaccine against the disease. Between 2010 and 2012, outbreaks were recorded in five Brazilian farms, and 34 W.ceti isolates were genetically characterized by repetitive extragenic palindromic PCR, enterobacterial repetitive intergenic consensus sequences PCR and pulsed-field gel electrophoresis. Two different W.ceti vaccines were tested: an aqueous-based whole-cell inactivated vaccine (bacterin) and oil-adjuvanted vaccine. Their efficacy was evaluated in rainbow trout at 30 and 60days post-vaccination (d.p.v.). W.ceti was found to be a highly homogeneous population in Brazil, with clonally related genotypes. Oil-adjuvanted vaccine exhibited the best (P<0.05) protection against disease, reaching relative percentage survival (RPS)values of 92% at 30 and 60d.p.v. Bacterin resulted in RPS values of 67% and 58% at day 30 and 60, respectively. The oil-adjuvanted vaccine provided effective protection against W.ceti infection in rainbow trout.